Hannah writes:

Dear TWiV,

On episode 218, Welkin Johnson recounted how the syringe broke as he got his flu shot and some of the vaccine ended up in the eye of his daughter. He asked whether this might have had any effect on her immunity. You said probably not given that it was an inactivated vaccine. I agree. You then wondered more generally whether it would be possible to get infected this way with a live virus. Then, last episode (225) you read a letter from a listener pointing to some studies of influenza infection following ocular infection of ferrets. You wondered how the virus got to the respiratory tract and whether this would happen in humans.

In short, Kathy is not “totally whacko.” The eyes and nose are indeed connected. I’d suggest this helpful review of the topic, written by some of the same folks. As the authors put it, “The nasolacrimal system, which provides an anatomical bridge between ocular and respiratory tissues. The lacrimal duct collects tear fluid from the ocular surface and transports it to the inferior meatus of the nose, facilitating the drainage of virus from ocular to respiratory tract tissues in a replication-independent manner, thus serving as a conduit for virus-containing fluid exchange between these sites.” The article also notes that ocular tissues have the cellular receptors for many respiratory viruses, meaning that in many cases, virus can replicate in the eyes. Think about that (or try not to) next time you rub your eyes…

Trudy writes:

Hi TWiVers!

I’m writing this email as an FU (stands for follow-up) to my email which was read on TWiV 225. In that email, I brought up the possibility of flu infection through the mucosa of the eye and forwarded you a couple of papers about this topic. Since you brought up the question of how the virus could end up in the respiratory tract, I decided to go straight to the source and ask my friend Jessica, who happens to be first author on those papers!

It turns out to be through the nasolacrimal duct, which is a little passageway that carries tears from the lacrimal sac (tear sac) into the nasal cavity. This also happens to be the reason why one sometimes need to blow one’s nose when crying. So Kathy was correct! Jessica also just wrote a great review article on this topic out in MMBR this month, which includes anatomical diagrams:


Hope this helps! All the best,


Robin writes:

Chicken gun http://en.m.wikipedia.org/wiki/Chicken_gun

Bill writes:


It is an unseasonably warm 5C here in Spokane (rhymes with can).

During the last episode, an individual wrote in to find the best way to learn basic cell biology. I agree that Alberts’ et al. MBOC or Lodish’s et al. MCB are far too advanced for most beginners to biology. However, books like Alberts’ et al. Essential Cell Biology should provide the basic fundamentals of biochemistry, central dogma, cell anatomy, and cell function to get a beginner on track. An older edition can be picked up for 1/10-1/20 of price of a new edition and is still perfectly adequate for their needs.

Great show!


Ricardo writes:

Hello TWIV gang. Something as beautiful as insightful. By http://www.informationisbeautiful.net

Ricardo Magalhaes, Ph.D.

Associate Professor of Microbiology

Steve writes:

Viruses in Podcast

From Nature.com

19:12 NewsChat

The new coronavirus has pandemic potential. Where did it come from, and how is it spread?


The above link is to the main podcast page for the episode. The audio link for the segment on coronavirus is down along on the left-hand side of the page, the 19:12 mark. I could not pull a direct link to the specific coronavirus audio segment otherwise I would have sent that.

News: Receptor for new coronavirus found


Ed writes:

Dear TWiV Hosts – I’m avoiding repetition this time by not listing names in case Alan gets too much attention ūüėČ

A couple of papers that came out in the March 1st issue of the Journal of Immunology may help shed some light on sensing foreign DNA in the cytoplasm. One is a review by Atlanand and Fitzgerald:

PubMed link: http://www.jimmunol.org/content/190/5/1911.full.pdf+html

The second is a paper that purports HSV capsids are broken down in the cytoplasm of myeloid cells, e.g. macrophages, by the proteasome, whereupon DNA is released to the cytosol for detection by IFI16.

PubMed: http://www.jimmunol.org/content/190/5/1911.full.pdf+html

This may be be worth some discussion.



Lucky Fractal writes:

Hello Doctor Racaniello,

I’m assuming you’ve probably read every virus related book out there.¬†Even so, I felt I had to send you this excerpt from “Virus X-Understanding the real threat of the new pandemic plagues” by Frank¬†Ryan. It struck me as a very poetic description of viruses. Feel free¬†to read in the podcast or not ūüôā



[Viruses] are also uniquely vulnerable. They cannot come to life¬†other than within the cells of their destined host. Consider the¬†uncertainty this creates.¬†To survive, a virus must constantly adapt and evolve. Every act of¬†infection involves a battle for access, a means of circumnavigating¬†the phagocytic defense system, followed by the adaptation to the¬†adamantine set-play rules of the genomic landscape itself. Once¬†established it has to compel the reluctant genetic mechanism to adopt¬†the progenitive programme of its own genome, then outwit the attempt ¬†of a now responding and extremely resourceful cellular and humoral¬†immune system, in order to survive once outside the amplifying cells.¬†It had to fight off myriad such forces bent upon its destruction¬†while discovering a way of leaving this host and finding another. One¬†solution to this, perhaps a very common solution, is for the virus to¬†discover a way of cohabiting with the infected host for a very long¬†time, perhaps for the remainder of the host’s life, with its¬†implications of de facto eternity through an evolution of vertical¬†transmission from parent to offspring.¬†The inference of such a relationship between two such dissimilar¬†forms of life is a much greater intimacy of give-and-take than the¬†anachronistic notion of pure predatorial aggression. Such refinements¬†of evolutionary partnership must flourish in the fields and jungles,¬†in the oceans, the soil and the the air, where over eons of evolution,¬†viruses have explored a multitude of wonderful,if often mysterious,¬†genomic archipelagoes, establishing relationships with every species,¬†extant or extinct, that has ever evolved on earth.

[End Quote]

Jessica writes:

Dear TWiVers,

thank you so much for episode 217! I am a PhD-student working on Influenza at the Robert Koch Institute in Berlin and I absolutely loved this episode! Actually, I listened to it twice to make sure that I got everything ūüôā

Furthermore, I wanted to ask you something – did you ever think about interviewing someone from the ecdc in Stockholm? No matter if it’s about a recent story like the novel coronavirus or infection epidemiology in general I think it would be an outstanding episode. I had the opportunity to meet Andrea Ammon at a conference in Berlin last year and she is totally great! Listening to her about her work during the SARS outbreak was absolutely fascinating and I am sure that she would be a perfect guest for TWiV! Maybe you consider asking her.


Last but not least, here is a reminder that you – Vincent – are invited to be a guest speaker at the ZIBI Summer Symposium 2013 “One Health” (June 10 and 11, 2013) here in Berlin! It would mean a lot to me and all TWiV-listeners in Germany if you could make it to Berlin! Please find attached the official invitation letter.

All the best from Germany and many thanks for your wonderful podcast that makes my long hours of marathon-training in the park so much more interesting!


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